Boundaries

Planetary boundaries
is the central concept in an Earth system framework proposed by a group of Earth system and environmental scientists led by Johan Rockström from the Stockholm Resilience Centre and Will Steffen from the Australian National University. In 2009, the group proposed a framework of “planetary boundaries” designed to define a “safe operating space for humanity” for the international community, including governments at all levels, international organizations, civil society, the scientific community and the private sector, as a precondition for sustainable development. This framework is based on scientific research that indicates that since the Industrial Revolution, human actions have gradually become the main driver of global environmental change. The scientists assert that once human activity has passed certain thresholds or tipping points, defined as “planetary boundaries”, there is a risk of “irreversible and abrupt environmental change”. The scientists identified nine Earth system processes which have boundaries that, to the extent that they are not crossed, mark the safe zone for the planet. However, because of human activities some of these dangerous boundaries have already been crossed, while others are in imminent danger of being crossed.

Environmental impacts are the unwanted byproduct of economic activities. Inadvertently, humans alter environmental conditions such as the acidity of soils, the nutrient content of surface water, the radiation balance of the atmosphere, and the concentrations of trace materials in food chains. Humans convert forest to pastureland and grassland to cropland or parking lots intentionally, but the resulting habitat change and biodiversity loss is still undesired. The environmental and health sciences have brought important insights into the connection of environmental pressures and ecosystem damages. Well-known assessments show that habitat change, the overexploitation of renewable resources, climate change, and particulate matter emissions are amongst the most important environmental problems. Biodiversity losses and ill health have been estimated and evaluated. This report focuses not on the effects of environmental pressure, but on its causes. It describes pressures as resulting from economic activities. These activities are pursued for a purpose, to satisfy consumption. Environmental pressures are commonly tied to the extraction and transformation of materials and energy. This report investigates the production-materials-consumption nexus.

Twenty-five years ago, the Union of Concerned Scientists and more than 1700 independent scientists, including the majority of living Nobel laureates in the sciences, penned the 1992 “World Scientists’ Warning to Humanity” (see supplemental file S1). These concerned professionals called on humankind to curtail environmental destruction and cautioned that “a great change in our stewardship of the Earth and the life on it is required, if vast human misery is to be avoided.” In their manifesto, they showed that humans were on a collision course with the natural world. They expressed concern about current, impending, or potential damage on planet Earth involving ozone depletion, freshwater availability, marine life depletion, ocean dead zones, forest loss, biodiversity destruction, climate change, and continued human population growth. They proclaimed that fundamental changes were urgently needed to avoid the consequences our present course would bring.

The authors of the 1992 declaration feared that humanity was pushing Earth's ecosystems beyond their capacities to support the web of life. They described how we are fast approaching many of the limits of what the ­biosphere can tolerate ­without ­substantial and irreversible harm. The scientists pleaded that we stabilize the human population, describing how our large numbers—swelled by another 2 billion people since 1992, a 35 percent increase—exert stresses on Earth that can overwhelm other efforts to realize a sustainable future (Crist et al. 2017). They implored that we cut greenhouse gas (GHG) emissions and phase out fossil fuels, reduce deforestation, and reverse the trend of collapsing biodiversity.

On the twenty-fifth anniversary of their call, we look back at their warning and evaluate the human response by exploring available time-series data. Since 1992, with the exception of stabilizing the stratospheric ozone layer, humanity has failed to make sufficient progress in generally solving these foreseen environmental challenges, and alarmingly, most of them are getting far worse (figure 1, file S1). Especially troubling is the current trajectory of potentially catastrophic climate change due to rising GHGs from burning fossil fuels (Hansen et al. 2013), deforestation (Keenan et al. 2015), and agricultural production—particularly from farming ruminants for meat consumption (Ripple et al. 2014). Moreover, we have unleashed a mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be annihilated or at least committed to extinction by the end of this century.

More than 15,000 scientists from 184 countries warn the evidence is clear: Current and future human health and wellbeing are at serious risk from climate change, deforestation, loss of access to freshwater, species extinctions, and human population growth.

Eminent scientists Jane Goodall, E.O. Wilson, and James Hansen are among those who have cosigned the warning, published Monday in the journal BioScience. The article, titled “World Scientists' Warning to Humanity: A Second Notice,” has 15,372 signatories in total, from a range of scientific disciplines. It is thought to be the largest-ever formal support by scientists for a journal article.

The “Second Notice” article updates the original “World Scientists' Warning to Humanity” document released in 1992, 25 years ago this month. Signed by 1700 scientists, including most of the living Nobel Prize science winners, it warned that human impacts on the environment were putting “at serious risk the future that we wish for human society” and detailed several worrisome trends.

Land use and related pressures have reduced local terrestrial biodiversity, but it is unclear how the magnitude of change relates to the recently proposed planetary boundary (“safe limit”). We estimate that land use and related pressures have already reduced local biodiversity intactness—the average proportion of natural biodiversity remaining in local ecosystems—beyond its recently proposed planetary boundary across 58.1% of the world’s land surface, where 71.4% of the human population live. Biodiversity intactness within most biomes (especially grassland biomes), most biodiversity hotspots, and even some wilderness areas is inferred to be beyond the boundary. Such widespread transgression of safe limits suggests that biodiversity loss, if unchecked, will undermine efforts toward long-term sustainable development.

Levels of global biodiversity loss may negatively impact on ecosystem function and the sustainability of human societies, according to UCL-led research.

“This is the first time we’ve quantified the effect of habitat loss on biodiversity globally in such detail and we’ve found that across most of the world biodiversity loss is no longer within the safe limit suggested by ecologists” explained lead researcher, Dr Tim Newbold from UCL and previously at UNEP-WCMC.

“We know biodiversity loss affects ecosystem function but how it does this is not entirely clear. What we do know is that in many parts of the world, we are approaching a situation where human intervention might be needed to sustain ecosystem function.”

The team found that grasslands, savannas and shrublands were most affected by biodiversity loss, followed closely by many of the world’s forests and woodlands. They say the ability of biodiversity in these areas to support key ecosystem functions such as growth of living organisms and nutrient cycling has become increasingly uncertain.

The study, published today in Science, led by researchers from UCL, the Natural History Museum and UNEP-WCMC, found that levels of biodiversity loss are so high that if left unchecked, they could undermine efforts towards long-term sustainable development.

Analysing 1.8m records from 39,123 sites across Earth, the international study found that a measure of the intactness of biodiversity at sites has fallen below a safety limit across 58.1% of the world’s land.

A sweeping new report released today emphasizes just how intertwined the challenges of climate change and loss of biodiversity truly are.

The Paris Climate Agreement and several other United Nations (UN) pacts “all depend on the health and vitality of our natural environment in all its diversity and complexity,” said Dr. Anne Larigauderie, executive secretary of the UN-backed organization behind the report. “Acting to protect and promote biodiversity is at least as important to achieving these commitments and to human well-being as is the fight against global climate change.”

The report comes from the efforts of more than 550 scientists in over 100 nations, corralled by an organization often dubbed “the IPCC for biodiversity.”

Much like the Intergovernmental Panel on Climate Change (IPCC) assesses the state of research on global warming and its impacts, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) reviews the best-available science on biodiversity and nature’s contributions to human well-being.

Climate Change not so Great for Wildlife

Three years in the making, the study concluded humans are causing the planet to lose species at such a rapid clip that the resulting risks are on par with those presented by climate change. On top of being unfortunate for those species that no longer exist, these losses also endanger people’s access to food, clean water, and energy, according to the report.

2019 Paris report

PARIS, 6 May – Nature is declining globally at rates unprecedented in human history – and the rate of species extinctions is accelerating, with grave impacts on people around the world now likely, warns a landmark new report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the summary of which was approved at the 7th session of the IPBES Plenary, meeting last week (29 April – 4 May) in Paris.

“The overwhelming evidence of the IPBES Global Assessment, from a wide range of different fields of knowledge, presents an ominous picture,” said IPBES Chair, Sir Robert Watson. “The health of ecosystems on which we and all other species depend is deteriorating more rapidly than ever. We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide.”

“The Report also tells us that it is not too late to make a difference, but only if we start now at every level from local to global,” he said. “Through ‘transformative change’, nature can still be conserved, restored and used sustainably – this is also key to meeting most other global goals. By transformative change, we mean a fundamental, system-wide reorganization across technological, economic and social factors, including paradigms, goals and values.”

“The member States of IPBES Plenary have now acknowledged that, by its very nature, transformative change can expect opposition from those with interests vested in the status quo, but also that such opposition can be overcome for the broader public good,” Watson said.

The IPBES Global Assessment Report on Biodiversity and Ecosystem Services is the most comprehensive ever completed. It is the first intergovernmental Report of its kind and builds on the landmark Millennium Ecosystem Assessment of 2005, introducing innovative ways of evaluating evidence.

Compiled by 145 expert authors from 50 countries over the past three years, with inputs from another 310 contributing authors, the Report assesses changes over the past five decades, providing a comprehensive picture of the relationship between economic development pathways and their impacts on nature. It also offers a range of possible scenarios for the coming decades.

Based on the systematic review of about 15,000 scientific and government sources, the Report also draws (for the first time ever at this scale) on indigenous and local knowledge, particularly addressing issues relevant to Indigenous Peoples and Local Communities.

Thus warns a landmark new report from the United Nations Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), presented at the 7th session of the IPBES Plenary meeting earlier this month in Paris.

Sir Robert Watson, Chair of the IPBES, said, “The health of ecosystems on which we and all other species depend is deteriorating more rapidly than ever. We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide.”

The Report highlights the urgency of global decarbonization and the need to increase nuclear power along with all other non-fossil energy sources. But while global warming will have a multiplier effect, this rapid decline in species is not just the result of climate change, but of humans all on their own.

Watson did say that it is not too late to make a difference. But we must start now at every level, from local to global, to make transformative changes, the type of changes the Nations of the World can’t seem to make on anything.

Nitrogen is absolutely crucial to life — an indispensable ingredient of DNA, proteins and essentially all living tissue — yet it also can choke the life out of aquatic ecosystems, destroy trees and sicken people when it shows up in excess at the wrong place, at the wrong time, in the wrong form. And over the past century, people have released so much of this type of nitrogen — known as reactive nitrogen — that scientists say we’ve passed the limit of what the planet can safely handle.

The world is using nitrogen fertilizer less and less efficiently. A greater proportion than ever before is washing into rivers and oceans. An environmental catastrophe looms, nitrogen scientists say, and the world urgently needs to develop strategies to prevent it.

Post-war physicists fearing nuclear apocalypse came up with the Doomsday Clock. In the 1980s, biologists contemplating ecological meltdown began talking about “biodiversity” loss as a way to tag and measure the crisis. Soon after, climate scientists recast concern over global warming with a warning that within a century it would lead to temperatures greater than any in human history.

Now, it is nitrogen’s turn.

Last month, in a seminar room at New York University, a score of nitrogen experts from around the world began drawing up scenarios of what a future nitrogen-soaked planet might look like – and to devise simple metrics for encouraging a global effort to head off disaster.

They met as part of the International Nitrogen Management System, a five-year, $60-million research project from the UN Environment Programme and the Global Environment Facility, that is intended, says its chief Mark Sutton, as nitrogen’s equivalent to the Intergovernmental Panel on Climate Change.

The bottom line, many there concluded, was that we must halve the amount of nitrogen we dump into the environment by mid-century or our ecosystems will face epidemics of toxic tides, lifeless rivers, and dead oceans. And that to do that will require, among other things, almost doubling the efficiency of nitrogen use on the world’s farms.

Phosphorus

Concern over nonpoint source P losses from agricultural lands to surface waters in frigid climates has focused attention on the role of freezing and thawing on P loss from catch crops (cover crops). This study evaluated the effect of freezing and thawing on the fate of P in bare soils, soils mixed with dairy manure, and soils with an established catch crop of annual ryegrass (Lolium multiflorum L.). Experiments were conducted to evaluate changes in P runoff from packed soil boxes (100 by 20 by 5 cm) and P leaching from intact soil columns (30 cm deep). Before freezing and thawing, total P (TP) in runoff from catch-cropped soils was lower than from manured and bare soils due to lower erosion. Repeated freezing and thawing significantly increased water-extractable P (WEP) from catch crop biomass and resulted in significantly elevated concentrations of dissolved P in runoff (9.7 mg L(-1)) compared with manured (0.18 mg L(-1)) and bare soils (0.14 mg L(-1)). Catch crop WEP was strongly correlated with the number of freeze-thaw cycles. Freezing and thawing did not change the WEP of soils mixed with manures, nor were differences observed in subsurface losses of P between catch-cropped and bare soils before or after manure application. This study illustrates the trade-offs of establishing catch crops in frigid climates, which can enhance P uptake by biomass and reduce erosion potential but increase dissolved P runoff.

Ocean acidification

Global carbon dioxide emissions are triggering permanent changes to ocean chemistry along the North American West Coast that require immediate, decisive action to combat.

That action includes development of a coordinated regional management strategy, concluded a panel of scientific experts including Andrew Dickson, a professor of marine chemistry at Scripps Institution of Oceanography at UC San Diego.

A failure to adequately respond to this fundamental change in seawater chemistry, known as ocean acidification, is anticipated to have devastating ecological consequences for the West Coast in the decades to come, the 20-member West Coast Ocean Acidification and Hypoxia Science Panel warned in a comprehensive report unveiled April 4.

Beneath northern India’s irrigated fields of wheat, rice, and barley ... beneath its densely populated cities of Jaiphur and New Delhi, the groundwater has been disappearing. Halfway around the world, hydrologists, including Matt Rodell of NASA, have been hunting for it.

Where is northern India’s underground water supply going? According to Rodell and colleagues, it is being pumped and consumed by human activities -- principally to irrigate cropland -- faster than the aquifers can be replenished by natural processes. They based their conclusions -- published in the August 20 issue of Nature -- on observations from NASA’s Gravity Recovery and Climate Experiment (GRACE).

"If measures are not taken to ensure sustainable groundwater usage, consequences for the 114 million residents of the region may include a collapse of agricultural output and severe shortages of potable water," said Rodell, who is based at NASA’s Goddard Space Flight Center in Greenbelt, Md.